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INFORMATION TECHNOLOGY
FUNDAMENTALS
Lecture One
Essential Computer
Concepts
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Class Website
www.blackdecimal.com
http://blackdecimal.com/category/infotech
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Course Textbook - Recommended
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Session Objectives
• Compare the types of computers
• Describe the components of a computer
system
• Examine data representation and the ASCII
code
• Learn about processing hardware
• Define memory and storage
• Describe input and output peripheral devices
• Discuss the types of system software and
their functions
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LEARNING ABOUT THE
COMPONENTS OF
COMPUTER SYSTEMS
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What Is a Computer?
A computer is an electronic device, operating
under the control of instructions stored
in its own memory, that can accept data,
process the data according to specified rules,
produce results, and store the results for
future use.
Computer is an electronic device that accepts
inputs from a user, manipulates the inputs
according to the instructions, displays the
output and stores the information for retrieval
later.
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Data Vrs Information
Data is a collection of unprocessed items,
which can include text, numbers, images,
audio, and video.
Information conveys meaning and is useful
to people.
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VISUAL OVERVIEW
The motherboard and the
microprocessor, the hard
disk, and the cards that
expand the capabilities of
the motherboard are
inside the tower in a
desktop computer.
The monitor is the device
that displays the output
from a computer.
The keyboard is the most
frequently used input device
The most popular pointing
device for a desktop
computer is a mouse.
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Types of Computers
• Personal computers (PCs) are computers
typically used by one person in a home or office.
• A PC is used for general computing tasks such
as word processing, manipulating numbers,
working with photographs or graphics,
exchanging email, and accessing the Internet.
• Examples are desktop computer, a notebook,
computer, a tablet PC, or a handheld computers.
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Laptop computer
Desktop computer
Smartphone
Netbook
Tablet PC
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• Mainframe computers are typically used by larger
businesses and government agencies to centrally store,
process, and manage large amounts of data.
• Supercomputers are the largest and fastest types
computers, they were first developed for high-volume
computing tasks such as weather prediction.
They are also used by large corporations and
government agencies when the tremendous volume of
data would seriously delay processing on a mainframe
computer.
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A mainframe computer
A supercomputer
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Computer Systems
• A computer system includes computer hardware and
software.
• Hardware refers to the physical components of a
computer.
• Software refers to the intangible components of a
computer system, particularly the programs, or lists of
instructions, the computer needs to perform a specific
task.
• Architecture or configuration. - The design and
construction of the hardware of a particular computer.
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Data Representation
• Data refers to the words, numbers, figures,
sounds, and graphics that describe people,
events, things, and ideas.
• a computer represents “on” with a 1 and “off”
with a 0. These numbers are referred to as
binary digits, or bits.
• A series of eight bits is called a byte
• A kilobyte (KB or simply K) is 1024 bytes, or
approximately one thousand bytes
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• megabyte (MB) is 1,048,576 bytes, or about
one million bytes;
• a gigabyte (GB) is 1,073,741,824 bytes, or
about one billion bytes;
• and a terabyte (TB) is 1024 GB, or
approximately one trillion bytes.
• The symbols KB, MB, GB, and TB refer to
processing capacity, storage capacity, and
file sizes.
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Personal computers commonly use the ASCII
code to represent character data.
• ASCII (pronounced “ASK-ee”) stands for
American Standard Code for Information
Interchange.
• The ASCII system translates the decimal
numbers 0–255 into binary data.
• Computers translate ASCII into binary data
so that they can process it.
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Computers that run the Windows operating
systems use the set of Extended ASCII
definitions defined by the American National
Standards Institute (ANSI)
Character ASCII
Code
ASCII Code
Binary Number
(space)
32
00100000
$
36
00100100
A
65
01000001
a
97
01100001
?
129
10000001
é
233
11101001
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Processing Hardware
• The hardware and the software of a
computer system work together to process
data and commands.
• Modifying data is called processing.
• Commands are instructions to the computer
on how to process the data.
• For example, you issue a command in the word
processing program to instruct the computer to
center the title in a report.
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Motherboard
The motherboard is a circuit board, which is a rigid piece of
insulating material with circuits, or electrical paths, on it
that control specific functions.
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Microprocessor
• Microprocessor is also called the processor or the
central processing unit (CPU)
• It consists of transistors and electronic circuits on
a silicon chip (an integrated circuit embedded in
semiconductor material).
• The processor is mounted on the motherboard
and is responsible for executing instructions to
process data.
• The speed of the microprocessor determines how
fast a computer processes data and executes
instructions.
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Microprocessor
Microprocessor (front and back views)
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Cards
• Cards are removable circuit boards that
are inserted into slots on the motherboard
to expand the capabilities of the
motherboard.
• A sound card, for example, translates the
digital audio information from the
computer into analog sounds that the
human ear can hear.
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Types of Memory and Storage
MEMORY AND STORAGE
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Memory
• Random access memory (RAM) consists of chips
on cards that plug into the motherboard,
temporarily holds programs and data while the
computer is on, and allows the computer to access
that information randomly.
• RAM is considered volatile memory or temporary
memory because it constantly changes while the
computer is on and clears when the computer is
turned off
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• Cache memory, sometimes called RAM cache
or CPU cache, is a special, high-speed memory
chip on the motherboard or CPU.
• Because the computer can access cache
memory more quickly than RAM, frequently
and recently accessed data and commands are
stored there instead of in RAM.
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• Virtual memory is space on the computer’s
storage devices that simulates additional
RAM.
• It enables programs to run as if your
computer had more RAM when all of the
available RAM is being used.
• It moves data and commands from RAM to
the computer’s permanent storage device to
allow space for new data and commands.
• Virtual memory is slower than RAM.
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• Read-only memory (ROM) also called nonvolatile
memory or permanent memory is a chip on the
motherboard prerecorded with instructions the
computer uses to check its components to ensure
they are working.
• It also activates the software that provides the basic
functionality of the computer when you turn on the
computer.
• The boot process is the set of events that occurs
between the moment you turn on the computer and
the moment you can begin to use the computer.
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• Complementary
metal
oxide
semiconductor (CMOS, pronounced “SEEmoss”) memory is a chip installed on the
motherboard that is activated during the
boot process and identifies where essential
software is stored.
• A small rechargeable battery powers
CMOS so its contents are saved when the
computer is turned off.
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• Unlike ROM, which cannot be changed,
CMOS changes every time you add or
remove hardware; therefore, CMOS is
often referred to as semipermanent
memory.
• CMOS stores the date and time because it
retains its contents when the computer is
turned off.
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Storage Media
• On a computer, all data and instructions are
stored as files.
• A computer file is a named collection of
stored data.
• An executable file contains the instructions
that tell a computer how to perform a specific
task.
• A data file is created by a user; for instance, a
report you write with a word processing
program can be saved as a data file.
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• Magnetic storage media store
magnetized particles on a surface.
data
as
• The most common magnetic storage device, a
hard disk, also called a hard disk drive.
• A hard disk contains several magnetic oxidecovered metal platters that are usually sealed
in a case inside the computer.
• You can also purchase external hard drives for
extra or backup storage.
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• Optical storage devices are polycarbonate discs
coated with a reflective metal on which data is
recorded using laser technology as a trail of tiny
pits or dark spots on the surface of the disc.
• Compact disk memory (CD)—you can read from
them, but you cannot record additional data onto
them.
• On a CD-R, after the data is recorded, you cannot
erase or modify it, but you can add new data to the
disc, as long as the disc has not been finalized.
• In contrast, you can re-record a CD-RW.
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• Recordable DVD drives are also available. As
with CDs, you can buy a DVD to which you can
record only once, or a rewritable DVD to which
you can record and then re-record data.
• Recordable DVDs come in two formats, DVD-R
and DVD+R, and likewise re-recordable DVDs
come in two formats, DVD-RW and DVD+RW.
• DVD drives on new computers are capable of
reading from and writing to both -RW and +RW
DVDs and CDs, as well as DVDs with two layers
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• Flash memory (also called solid
state storage) is similar to ROM
except that it can be written to
more than once.
• Flash memory cards are small,
portable cards encased in hard
plastic to which data can be
written and rewritten.
• They are used in digital cameras,
handheld computers, video game
controllers, and other devices.
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• A popular type of flash memory is
a USB flash storage device, also
called a USB drive or a flash
drive.
• USB drives for PCs are available in
a wide range of sizes from 1 to 64
GB of data.
• They are becoming more popular
for use as a secondary or backup
storage device for data typically
stored on a hard disk drive.
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Types of Input and Output devices
INPUT AND OUTPUT
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• The data or instructions you type into the
computer are called input.
• The result of the computer processing
your input is referred to as output.
• The computer takes care of the processing
function;
you
need
additional
components, called peripheral devices, to
accomplish the input and output
functions.
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Input Devices
• You use an input
device, such as a
keyboard or a mouse,
to input data and
issue commands.
• The computer can
also receive input
from a storage device.
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• A scanner is a device that transfers the
content on a piece of paper into memory
• Microphones are another type of input
device.
• Input devices can be connected to the
computer with cables or via a wireless
connection.
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Output Devices
The most common
devices for displaying
output are monitors
and printers
Laser Printer
Inkjet Printer
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Monitor
• The most common devices for displaying output
are monitors and printers. Most flat panel
monitors use LCD (liquid crystal display)
technology, which creates the image you see on
the screen by manipulating light within a layer of
liquid crystal.
• Flat-panel monitors labeled as LED (light
emitting diode) monitors use LEDs to provide
the backlight. LED backlighting is more energy
efficient than ordinary backlighting. One problem
with LCD is that when you view the monitor
from an angle, it can be hard to see the images on
it. LED backlighting helps solve this problem.
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• Factors that influence the quality of a monitor’s
output are screen size, resolution, and dot
pitch.
• Screen size is the diagonal measurement in
inches from one corner of the screen to the other.
• Resolution is the number of pixels the monitor
can display.
– Standard resolutions range from 640 × 480 to
1600 × 1200.
• Dot pitch (dp) measures the distance between
pixels, so a smaller dot pitch means a sharper
image. A .28 or .26 dp is typical for today’s
monitors.
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Printer
• A printer produces a paper copy of the text or
graphics processed by the computer.
• The most popular printers for business use are
laser printers. They use the same technology as
a photocopier; a temporary laser image is
transferred onto paper with a powdery
substance called toner. The speed of laser
printers is measured in pages per minute
(ppm).Color laser printers use several toner
cartridges to apply color to the page.
• A less expensive alternative to the laser printer is
an inkjet printer.
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Data Communication
• The transmission of text, numeric, voice,
or video data from one computer to
another or to a peripheral device.
• The four essential components of data
communications are;
–
–
–
–
Sender : The origin of the message
Receiver : The destination of the message
Channel : The medium for the data transfer
Protocol: The rules that establish an orderly
transfer of data between the sender and the
receiver
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Data Bus
Refers to the path
between
the
microprocessor, RAM,
and peripherals that
data pass through to
other devices and parts
of the computer.
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Networks
• A network connects one computer to other
computers and peripheral devices,
enabling you to share data and resources
with others.
• Basic characteristics
–
–
–
–
–
Network interface card (NIC)
Network Operating System
Client
Server
Other peripherals (Routers, Access points etc)
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Typical Networking Environment
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Telecommunication
• It refers to a communicating over a
comparatively long distance using a
phone line or some other data conduit.
• To make this connection, you must use a
modulator-demodulator (modem). The
modem converts the digital signals into
analog, or continuous wave, signals
(sound waves) that can traverse ordinary
phone lines.
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Internet
• The Internet is the largest network in the
world, connecting millions of people. It is
referred to as network of networks.
• With an internet connection, you can have
access to the resources on the world wide
web.
• Hence, the internet is the physical
connection and the web is a collection of
sites that offer text & graphics and sound
& animation resources through the
hypertext transfer protocol resources.
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Security Threats
• Security refers to the steps a computer
owner takes to prevent unauthorized use
of or damage to the computer.
• Threats are activities, people, & programs
that is a source of danger to computer
systems.
• Examples of computer security threats are
Malware, Viruses, Spyware, Adware etc.
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• Malware: is a broad term that describes any
program that is intended to cause harm or
convey information to others without the
owner’s permission.
• Virus: A software program capable of
reproducing itself and usually capable of
causing great harm to files or other programs
on the same computer. Worms and Trojan
horses are specific types of viruses.
• Antiviruses are software that checks a
computer for viruses and prevents their
spread.
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Computer Software
• Software is defined as written programs,
procedures or rules and associated
documentation that direct the computer
to accomplish a task.
• Software are divided into two major
categories:
System
Software
and
Application Software.
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Systems Software
• System software helps the computer carry
out its basic operating tasks.
• System
software
manages
the
fundamental operations of the computer,
such as loading programs and data into
memory, executing programs, saving data
to disks, displaying information on the
monitor, and transmitting data through a
port to a peripheral device.
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Types of Systems Software
• Operating Systems: operating system
controls basic input and output, allocates
system resources, manages storage space,
maintains security, and detects equipment
failure. E.g. Windows, Macintosh, Linux
• Utilities: Are programs that augments the
operating system by taking over some of its
responsibility for allocating hardware
resources. E.g. Antivirus, Backup, Firewall
• Device Drivers: Handle the transmission
protocol between a computer and its
peripherals. E.g. Drivers
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Application Software
• Application software helps the user carry
out a variety of tasks.
• Application software has a variety of
uses:
1. To make business activities more efficient.
2. To assist with graphics and multimedia
projects.
3. To support home, personal, and educational
tasks.
4. To facilitate communications.
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Types of Application Software
• Business: Is an application software that
assists people in becoming more effective
and efficient while performing their daily
business activities. E.g. Microsoft Office
• Graphics and Multimedia: E.g. CAD,
Photoshop, Illustrator, Desktop Publishing
• Home/ Personal / Educational: E.g. Encarta,
Personal Microsoft Office, Personal Email
clients, CBTs etc.
• Communication: E.g. Web browsers, IM
apps, blogs, etc.
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COMPUTING IN THE CLOUD
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Cloud computing
• Cloud computing means that data, applications,
and even resources are stored on servers accessed
over the Internet rather than on users’ computers,
and you access only what you need when you
need it.
• Some companies provide space and computing
power to developers for a fee.
• Individuals might subscribe to a backup service
such as Carbonite or Mozy so that their data is
automatically backed up on a computer at the
physical location of those companies.
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• Google Docs and Microsoft Web Apps provide
both free and paid versions of various applications
that you access by logging in to their Web sites.
• In addition to using services over the Internet,
many people store files on servers accessed over the
Internet.
• For example, SkyDrive is space on Windows Live
servers where you can store up to 25 GB of files in
public or private folders or in folders that you make
available to only people you specify.
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Reference
Ann Shaffer, Patrick Carey, June Jamrich
Parsons and Dan Oja (2010).
New
Perspectives on Microsoft Office 2010, First
Course, Course Technology.
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